Text message and call dropping issue on my iPhone, post iOS 18.3.1 update

Ever since the 18.3 software update, my cellular service goes in and out randomly. I am able to start a call but it drops randomly and then I can’t even send text messages out. This was on an iPhone 15 pro max. I go to Apple and Verizon (my cellular company) and both think there must be a hardware issue with it, and suggest either fixing the phone or getting a new one. I ended up buying a 16 pro max and sure enough, same exact issue. It’s gotta be the software update, but I’m not seeing anything?

[Re-Titled by Moderator]